Discharge filter plate assembly for filter press

ABSTRACT

A filter plate assembly for a filter press is provided. The filter plate assembly includes at least a first filter plate and a second filter plate, which cooperate to define a filter chamber when the first filter plate and the second filter plate are in a filtering position. At least one of the first filter plate and the second filter plate is movable from the filtering position to a discharge position in which a filter cake can be discharged. In other configurations, the filter plate assembly can include a first filter plate, a second filter plate and a center filter plate or frame, which cooperate to define a filter chamber. The center filter plate or frame is movable from a filtering position to a discharge position.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 62/656,228, entitled “DISCHARGE FILTER PLATE ASSEMBLYFOR FILTER PRESS,” filed Apr. 11, 2018.

This application hereby incorporates by reference the above-identifiedprovisional application in its entirety.

BACKGROUND Field of the Invention

The present disclosure is related to an improved filter plate assembly,and related methods and devices, for separating solid and liquidcomponents from a mixture.

Description of the Related Art

Separating the liquid and solid components of a liquid-solid mixture, orslurry, is a necessary or desirable process in many industries. Onemethod of filtering slurries having relatively high concentrations ofsolid matter uses an apparatus known as a filter press. In existingfilter presses, the solid particulate “cake” remaining in a filtercavity must be removed in preparation for a subsequent filter cycle.This cleaning process has one or more disadvantages. In many cases, theremoval of the particulate cake requires that the filter plates beseparated from one another, individually or all at one time, to permitthe cake to be discharged from the filter cavity. Because as many as ahundred or more individual plates may be used, the cleaning process canbe very time-consuming.

In other cases, it is possible for particulate cake to be dischargedfrom the filter chambers of the filter press while the individual filterplates are maintained in a substantially compacted, or condensed,position. One way to accomplish this is to have a perimeter of eachfilter chamber configured to have an open section, as disclosed inApplicant's U.S. Pat. No. 7,396,472. A closure can be configured toclose the open section, and the closure is removable from the opensection to permit particulate cake to be removed from the filter chamberwhile the filter plates are in a condensed position. Although thisapproach allows for the individual filter plates to remain in acompacted, or condensed, position, methods and devices that currentlyexist for removing the cake under this approach may fail to completelydislodge or remove particulate matter remaining within the filterchamber after the particulate cake has been discharged. In addition,under this approach, the open section of the filter chamber can bedifficult to fully seal when the filter press is in use. Furthermore,under this approach, the sprayer assembly or spray nozzle of the filterpress wash apparatus is contained within the filter chamber. Aninterior, as opposed to exterior, wash mechanism such as this may resultin clogging or blockage of wash fluid within the filter chamber.

SUMMARY

One or more embodiments involve a filter plate assembly and/or a filterpress incorporating the filter plate assembly. The filter plate assemblycomprises at least a first filter plate and a second filter plate, whichcooperate to at least partially define a filter chamber when the firstfilter plate and the second filter plate are in a filtering positionaligned with one another along an operational axis. At least one of thefirst filter plate and the second filter plate is movable out ofalignment with the operational axis or in a direction normal to theoperational axis to a discharge position in which a filter cake can bedischarged from a portion of the filter chamber defined by the movablefilter plate(s). In some configurations, the discharge process can beexecuted automatically without the need for an operator. In someconfigurations, at least one support structure movably supports themovable filter plate(s) for movement between the filtering position andthe discharge position. In some configurations, the filter plateassembly comprises a first filter plate and a second filter plate,wherein one or both of the filter plates define a recessed cavity, whichdefines the filter chamber when the filter plates are in the filteringposition. In other configurations, the filter plate assembly comprises afirst filter plate, a second filter plate and a center filter plate orframe, as discussed further herein. One or both of the first filterplate and the second filter plate can also form a portion of anotherfilter plate assembly. For example, the second filter plate can form anend of one filter cavity on a first side of the second filter plate andan end of another filter cavity on a second side of the second filterplate.

In one embodiment, a filter plate assembly comprises a first filterplate having a first side surface, a second filter plate having a secondside surface, and a center plate or frame having an outer surface and aninterior region. The center plate or frame is configured to be movablebetween a filtering or aligned position and a discharge or separatedposition relative to the first filter plate and the second filter plate.In the filtering position, the center plate or frame is held in placebetween the first side surface and the second side surface. In thedischarge position, the first filter plate and the second filter plateseparate from the center plate a distance, thereby permitting the centerplate to drop or move toward or to the discharge position, whereuponparticulate cake is discharged from the interior region of the centerplate.

In another embodiment, a filter plate assembly comprises a first filterplate and a second filter plate. The first filter plate and the secondfilter plate have a filtering position in which the plates are alignedwithin one another along an operational axis and cooperate to at leastpartially define a filter chamber. The first filter plate is movable outof alignment with the second filter plate and away from the operationalaxis to a discharge position in which filter cake can be discharged froma portion of the filter chamber at least partially defined by at leastone of the first filter plate and the second filter plate.

An embodiment involves a filter plate assembly and/or a filter pressincorporating the filter plate assembly. The filter plate assemblycomprises at least a first filter plate and a second filter plate, whichcooperate to at least partially define a filter chamber. At least onesprayer assembly is movably supported relative to one or both of thefirst filter plate and the second filter plate. The at least one sprayerassembly is movable out of alignment with the operational axis or in adirection normal to the operational axis to direct a sprayed mediatoward one or both of the first filter plate and the second filterplate.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the present filterplate assembly are described with reference to the drawings of thepreferred embodiments. These embodiments are intended to illustrate, butnot to limit, the present invention.

FIG. 1 is a perspective view of a filter press incorporating a filterplate assembly having certain features, aspects, and advantages of thepresent invention. The filter plate assembly is shown in a retractedposition. The fluid hoses connecting the wash fluid source to thesprayer assemblies are removed.

FIG. 2 is a top view of the filter press of FIG. 1.

FIG. 3 is another perspective view of the filter press of FIG. 1.

FIG. 4 is a side view of the filter press of FIG. 1.

FIG. 5 is a perspective view of the filter press of FIG. 1 with thefilter plate assembly in an open or discharged position. The centerplates of the filter plate assembly are shown in an aligned (or up)position. The fluid hoses connecting the wash fluid source with thesprayer assemblies are shown.

FIG. 6 is a top view of the filter press of FIG. 5 with the fluid hosesremoved.

FIG. 7 is a perspective view of the filter press of FIG. 5 with thefluid hoses removed.

FIG. 8 is a side perspective view of the filter press of FIG. 5 with thefluid hoses removed.

FIG. 9 is a perspective view of the filter press of FIG. 5 with thecenter plates of the filter plate assembly shown in a separated (down ordischarge) position.

FIG. 10 is another perspective view of the filter press of FIG. 9 withthe fluid hoses removed.

FIG. 11 is a side perspective view of the filter press of FIG. 9 withthe fluid hoses removed.

FIG. 12 is a transverse view of a filter plate assembly comprising afirst filter plate, a second filter plate, and a center plate shownremoved from the filter press, along with associated vertical rails, andsprayer assemblies also removed from the filter press.

FIG. 13 is a side view of the filter plate assembly and associatedvertical rails, sprayer assemblies, and force generator of FIG. 12.

FIG. 14 is a perspective view of the filter plate assembly andassociated vertical rails, sprayer assemblies, and force generator ofFIG. 12.

FIG. 15 a perspective view of the filter plate assembly and associatedvertical rails, sprayer assemblies, and force generator of FIG. 12, withone of the filter plates removed.

FIG. 16 a perspective view of the filter plate assembly and associatedvertical rails, sprayer assemblies, and force generator of FIG. 12, withthe center plate shown in a separated (or down) position.

FIG. 17 a perspective view of the filter plate assembly and associatedvertical rails, sprayer assemblies, and force generator of FIG. 16, withone of the filter plates removed.

FIG. 18 is a perspective view of one filter plate having a recessedcavity of the filter plate assembly of FIG. 12.

FIG. 19 is a perspective view of the center plate of the filter plateassembly of FIG. 12.

FIG. 20 is a perspective view of a filter plate having a recessedcavity.

FIG. 21 is a perspective view of a filter plate assembly comprising afirst filter plate and a second filter plate shown removed from thefilter press, along with associated vertical rails, and sprayerassemblies also removed from the filter press. In the filter plateassembly of FIG. 21, at least one of the filter plates is a filter platehaving a recessed cavity as shown in FIG. 20.

FIG. 22 is a perspective view of the filter plate assembly andassociated vertical rails, sprayer assemblies, and force generator ofFIG. 21. The filter plate of FIG. 20 is shown in a separated (or down)position.

FIG. 23 is a perspective view of a filter press incorporating aplurality of filter plate assemblies, which omits the support rails ortracks for the movable filter plates. A linking element can engage morethan one of the movable filter plates to selectively move the movablefilter plates. One or more force generators can be configured to movethe linking element. In some configurations, the number of forcegenerators is less than the number of movable filter plates. The filterplate assemblies are shown in an open position and the movable filterplates in a down or discharge position.

FIG. 24 is a side view of the filter press of FIG. 23 with the fluidhoses removed.

FIG. 25 is a side view of the filter press of FIG. 23 with the fluidhoses removed and the filter plate assemblies shown in an aligned (orup) position.

DETAILED DESCRIPTION

A filter press is used to separate liquid and solid components from aliquid-solid mixture, such as a slurry or sludge. For example, thefilter press described herein is generally referred to by the referencenumeral 10 and can be used to filter a process liquid, industrial waste,municipal waste, or perform component separation in other settings. Thefilter press 10 may also be used in a variety of other industries. Thefilter press 10 includes a filter plate assembly, which is generallyreferred to by the reference numeral 100. The filter press 10 and/orfilter plate assembly 100 are configured, in at least some embodiments,to permit partially or fully automated discharge of the particulatecake. Such an arrangement can reduce operation costs by eliminating theneed for a person to perform manual cleaning of the filter plates, as iscommon with prior art filter presses.

In one embodiment, a filter plate assembly 100 includes a first filterplate 130, a second filter plate 130, a center plate or frame 120, and aforce generator 510. The first filter plate 130 and the second filterplate 130 each have handles (or other support structures) 132 onopposing sides of the plate 130. The handles 132 allow the filter plates130 to be supported by a pair of horizontal side rails 12. Preferably,the handles 132 slidably engage the upper surface of the side rails 12such that the filter plates 130 can be moved along the rails 12 topermit individual filter plates 130 to be separated from one another(e.g., to permit the filter plate assembly 100 to move from a retractedto an expanded position). The center plate 120 is supported so as to bemovable relative to the side rails 12 in a vertical direction. Thecenter plate 120 can be referred to as a movable plate. In otherembodiments, such as those in which the filter plate assembly 100 doesnot include a center plate 120 (e.g., a recessed cavity platearrangement, such as that shown in FIGS. 20-22), the movable plate canbe any plate(s) of the filter plate stack, including but not limited toone or both of the first filter plate 130 and the second filter plate130. Similarly, instances of the term “center plate” in the presentdisclosure can be replaced with the term “movable plate” in view ofembodiments in which plates other than the center plate are movable,unless indicated otherwise. In some configurations, the center plate120, which rides or slides within a pair of vertical rails or tracks 18supported by or relative to the side rails 120, is movable between analigned position (upper position as shown) and a separated position(lower position as shown) relative to the first filter plate 130 and thesecond filter plate 130. When moving to the separated position, thecenter plate 120 drops or falls toward the ground under the force ofgravity or is forcibly moved by the force generator 510. Preferably, thecenter plate 120 remains slidably engaged with the vertical rails 18upon moving to or toward the separated position. The force generated bythe center plate 120 suddenly stopping after dropping or being forciblymoved to the separated position results in the removal of particulatecake from the interior of the center plate 120. The center plate 120 ismade to withstand the sudden stop after dropping or being moved to theseparated position.

In a preferred embodiment, the force generator 510 is a pneumaticcylinder which utilizes a compressed gas (e.g., air) as its operatingfluid. In other embodiments, the force generator can be a hydrauliccylinder, a screw jack, or any other suitable arrangement. In someconfigurations, the filter plate assembly 100 or associated filter press10 does not include a force generator. For example, the movable filterplate 120 may be manually moved between the filtering or alignedposition and the discharge position. While in the aligned position, thecenter plate 120 is situated in between a surface of the first filterplate 130 and a surface of the second filter plate 130, and ismaintained in position by the force exerted by the pneumatic cylinderuntil such time that the filter plates of the filter press 10 aresqueezed together in a sealed manner at which point the center plate 120is held in place by squeezing force of the first and second plates 130.To move to the separated position, the center plate 120 is either nolonger supported by the force of the pneumatic cylinder or the pneumaticcylinder pulls the center plate 120 downward toward or to the separatedposition. For example, the separated position is attained when thecompressed gas of the pneumatic cylinder is vented or released to theatmosphere and allows the center plate 120 to fall to the separatedposition. The pneumatic cylinder can be used to lift the center plate120 back to the aligned position once the cleaning process is complete.Alternatively, the pneumatic cylinder can pull the center plate 120toward or to the separated position and can also be used to raise thecenter plate 120 back to the aligned position. The pneumatic cylinder(or other force generator) can be provided for each center plate 120 orcan be configured to operate multiple center plates of the multiplefilter plate assemblies of a filter press.

In some embodiments, the interior region of the center plate 120 atleast partially defines a filter chamber 124 as shown in FIG. 15, thefilter chamber 124 having openings on each side of the center plate 120.While in the aligned position, the openings on each side of the centerplate 120 are bounded and, in when the plates are pressed against oneanother, sealed by the surfaces of the first filter plate 130 and thesecond filter plate 130 such that the filter chamber 124 is in a closedposition. The surfaces of the filter plates 130 facing the filterchamber 124 and bounding the filter chamber openings in the closedposition are planar or generally planar such that the entire thicknessof the filter chamber 124 is determined by the thickness of the centerplate 120. In other embodiments, the filter chamber is defined, in partor in whole, by recessed cavities in adjacent filter plates.

In other embodiments, instead of the center plate 120 dropping orfalling to the ground solely under the force of gravity, the centerplate or frame 120 is additionally pulled down by human force. Thecenter plate 120 is made to withstand the sudden stop upon reaching theseparated position, even when pulled down by human force.

In some embodiments, the vertical rails 18 that support the center plate120 are supported by or at least limited in movement by the side rails12, which support the first and second filter plates 130. Such anarrangement is well-suited for retrofit applications. Although referredto as vertical rails, the rails 18 may be provided in otherorientations, as discussed herein. Accordingly, it is not intended tolimit the rails to a vertical orientation unless specifically indicated.In other embodiments, the center plate 120 rides within a pair ofvertical rails 18 which are supported by a pair of hanging rails 14situated above the pair of side rails 12. Preferably, a connection, suchas a brace or strut 200, extends between and can connect the verticalrails 18. The brace 200 is supported by the hanging rails 14 and enablesthe vertical rails 18 to slidably move relative to the upper surface ofthe hanging rails 14. Optionally, the vertical rails 18 can be furtherstabilized by a pair of frame retention rails 16 situated below the pairof side rails 12. Such an arrangement can provide greater stability tothe vertical rails 18. However, other suitable arrangements forsupporting the movable plate(s) 120 can be employed. For example, themovable plate(s) 120 can be supported directly or indirectly by theforce generator 510 or other support structure that moves or facilitatesmovement of the movable plate(s) 120. In some configurations, themovable plate(s) 120 can be directly supported only by the bracket 202,force generator 510 and brace 200. In other words, the vertical rails 18and any corresponding structure can be omitted. Furthermore, in otherconfigurations, the movable plate(s) 120 may not be directly supportedat all. The side rails 12 of the filter press 10 can generally capturethe movable plate(s) 120 and keep them in a position associated with thefilter press 10.

In other embodiments, the center plate or movable plate 120 is providedwith a wash apparatus 300 or components of a wash apparatus 300. Thewash apparatus 300 is connected to a wash fluid source 400. The washapparatus 300 comprises one or more sprayer assemblies or spray nozzles310, 320. The sprayer assembly or spray nozzle 310, 320 is attached toan outer surface of or is otherwise movable along with the center plate120, and resides exterior to each of the first filter plate 130, thesecond filter plate 130, and the center plate 120. Advantageously, suchan arrangement allows for easier cleaning of the filter chamber 124.When the center plate or movable plate 120 is moved up or down relativeto each of the first filter plate 130 and the second filter plate 130,the sprayer assembly 310, 320 moves with the center plate or movableplate 120 and washes or cleans the filter media of the first and second(or adjacent) filter plates 130. In the illustrated arrangement, thesprayer assembly 310, 320 is supported by a bracket 202, such as aninverted U-shaped bracket, that is connected to the center plate 120.

In other embodiments, the pair of hanging rails 14 can be provided withother devices or apparatuses. Alternatively, the pair of hanging rails14 can serve as a pair of dedicated support rails, i.e., rails thatserve only to support the vertical rails 18 within which the centerplate or movable plate 120 rides. In other embodiments, the pair ofdedicated support rails can be a pair of rails other than the pair ofhanging rails 14.

Although in the illustrated arrangement, the center plate or movableplate 120 moves vertically downward relative to the first and secondfilter (or adjacent) plates 130 to take advantage of gravity acting tomove the center plate or movable plate 120; such an arrangement is notrequired. The center plate or movable plate 120 can move out of registrywith the first and second filter (or adjacent) plates 130 in anydirection. In other words, in a filtering position, the filter plates130 can be aligned along a longitudinal axis, which can be referred toas an operational axis. The movable filter plate(s) 120 can be moved inany direction that is normal to the operational axis or has a componentof movement that is normal to the operational axis. For example, theplates 120 can be movable in a horizontal or vertical direction, or canbe rotated about an axis, such as an axis that is displaced from theoperational axis and that can be parallel to the operational axis. Sucharrangement may allow better access to a receptacle for the particularcake or may be necessitated by lack of available space below the filterpress 10.

Another embodiment is shown in FIGS. 1-19. Components, features, andadvantages of other embodiments, that are not otherwise described orshown in FIGS. 1-19, can be included in this embodiment. Additionally,components, features, and advantages of this embodiment can be includedin other embodiments.

In the embodiment of FIGS. 1-19, a filter plate assembly 100 includes afirst filter plate 130, a second filter plate 130, and a center plate orframe 120. In the illustrated arrangement, the filter press 10 alsoincludes a set of force generators 500; however, as discussed above, itis possible to have arrangements in which there are no force generators500 and the movable plates are moved manually or via some othermechanism. The interior region of the center plate 120 defines a filterchamber 124 (as shown in FIG. 15), the filter chamber 124 having anopening on each side of the center plate 120. While in an alignedposition, the openings on each side of the center plate 120 can bebounded and sealed by the surfaces of the first filter plate 130 and thesecond filter plate 130 such that the filter chamber 124 is in a closedposition. FIGS. 1-4 show the filter plate assembly 100 in a retractedposition with the center plates 120 of the filter plate assembly 100 inan aligned position relative to the first and second filter plates 130.The surfaces of the filter plates 130 facing the filter chamber 124 andbounding the filter chamber openings in the closed position are planaror generally planar such that the entire thickness of the filter chamber124 is determined by the thickness of the center plate 120. However, asdiscussed above, the filter plate assembly 100 could include a set offilter plates having recessed cavities that cooperate with an adjacentfilter plate to define a filter chamber. In such an arrangement, theinterior plates typically have a cavity on each side such that aparticular plate cooperates with the cavity of the adjacent plate oneach side to define a filter chamber with each adjacent filter plate.The end plates typically have a cavity only on the interior side. Thus,thickness of the filter chamber is partially defined by the cavity ofeach filter plate. The description below is in the context of anassembly having a center plate 120; however, the same description canapply to a plate assembly having recessed cavities. Accordingly,reference to the center plate 120 can refer to any movable plate of aplate assembly having recessed cavities.

As shown for example in FIGS. 1, 3-5, and 7-11, the set of forcegenerators 500 comprises a force generator 510 provided for each centerplate 120. Each force generator 510 is located and held in a positionabove the respective center plate 120. For example, each force generator510 can be supported by the brace 200 and can be connected to the centerplate 120 via the bracket 202. The force generators 510 facilitate thedownward and/or upward movement of the center plate 120 (relative to thefirst filter plate 130 and the second filter plate 130) during and afterdischarge of particulate cake from the filter chamber 124. The forcegenerator 510 can push the center plate 120 downward toward or to aseparated position relative to the first filter plate 130 and the secondfilter plate 130. Alternatively, the center plate 120 can drop or fallto the ground or to a separated position (any lower position as shown)solely under the force of gravity. FIGS. 9-11 show the filter plateassembly 100 in an expanded position with the center plates 120 of thefilter plate assembly 100 in a separated (or down) position relative tothe first and second filter plates 130. The force generator 510 can alsobe used to lift the center plate 120 upward back to the alignedposition. In each of these cases, the center plate 120 preferably ridesor slides within a pair of vertical rails 18 which are supported by oneor both of a pair of side rails 12 and a pair of hanging rails 14. FIGS.5-8 show the filter plate assembly 100 in an expanded position with thecenter plates 120 of the filter plate assembly 100 in an aligned (or up)position relative to the first and second filter plates 130. Theposition of the center plates 120 shown in FIGS. 5-8 can be eitherbefore the center plates 120 are moved to the separated position (underthe force of the force generators 510 or solely under the force ofgravity) or after the center plates 120 have been lifted upward back tothe aligned position (and before the filter plate assembly 100 has beenreturned to a retracted position).

The force generators 510 are supported directly or indirectly by a pairof hanging rails 14. The force generators 510 can be pneumatic cylinderswhich utilize a compressed gas as its operating fluid. The forcegenerators 510 can also be hydraulic cylinders. Other types of forcegenerators 510 can also be used. Moreover, the force generators 510 canbe located in any suitable location to move the movable filter plates120. For example, as shown in FIGS. 1, 3-5, and 7-11, the forcegenerators 510 can be positioned above each respective center plate 120.The force generators 510 can also be located below each respectivecenter plate 120. In some configurations, the force generators 510 arepneumatic cylinders located either above or below the center plates 120and that exert a pressure of, for example, approximately 100 lbs each.In other configurations, instead of having a dedicated force generator510 for each center plate 120, a single force generator can be providedthat is coupled (or that can be coupled) to multiple center plates 120,such as a sub-set or all of the center plates 120. For example, twoforce generators can be provided, in the form of hydraulic cylinders,each of the hydraulic cylinders coupled to about half of the availablecenter plates 120 and configured to exert a pressure of, for example,approximately or up to 5000 lbs each.

In addition to providing force to facilitate upward and/or downwardmovement of each center plate 120, the force generators 510,individually or in combination, can be used to provide the forcenecessary to maintain the first filter plate 130, the second filterplate 130, and the center plate 120 in the aligned position. In thealigned position, the center plate 120 is situated in between a surfaceof the first filter plate 130 and a surface of the second filter plate130, and is maintained in position by the force exerted by the forcegenerator(s) 510. However, generally, a dedicated force generator (orforce generators), separate from the force generators 510 associatedwith each center plate 120, will be provided for this purpose and willcompress the collection of filter plate assemblies in an axial directionin a manner similar to or the same as conventional filter presses.

In a typical filter plate assembly 100 comprising a first filter plate130 and a second filter plate 130 (and no center plate 120), the firstand second filter plates 130 are squeezed or held together by a pressureof up to 3,000-4,000 lbs, or even up to 10,000 lbs or more in someconfigurations, in order to maintain a seal between the filter plates130 at the treatment pressures, which can be about 100 psi in thefiltering mode and 200-250 psi in a membrane filter cake squeeze mode.In the embodiment of FIGS. 1-19, the first filter plate 130, the secondfilter plate 130, and the center plate 120 can be squeezed or heldtogether by a higher force compared to a recessed cavity plate assemblybecause the center plate 120 may be more susceptible to deformation thana recessed cavity plate. Furthermore, in at least some configurations,the center plates 120 can be held in the aligned position by thissqueezing force without assistance from the force generators 510 used tomove the center plates 120 into and out of the aligned position.

The pressure created within the cavity defined by the first filter plate130, the second filter plate 130, and center plate 120 in an aligned orsealed position during the filtering process can result in the centerplate 120 expanding in a radial direction as a result of the internalpressure. The side rails 12 can provide support to inhibit expansion, ina radial direction, in response to the forces generated by the internalpressure. In addition, or alternatively, the first and second filterplates 130 and the center plate 120 can be keyed together to inhibitexpansion of the center plate 120, in a radial direction, in response tothe compressive forces and/or in response to fluid pressure within thefilter chamber. Preferably, both sides of the center plate 120 have keyrecesses 122 (shown in FIGS. 15-17 and 19) that are adapted to mate withcorresponding keys of the first and second filter plates 130. In thisway, both the first and second filter plates 130 are keyed to the centerplate 120. The key recess 122 can be a hole or other structure that isconfigured to receive a structure on the filter plate 130.Alternatively, the center plate 120 can have keys or protrusions on eachside that are configured to be received within key recesses of thefilter plates 130. In other embodiments, the filter plates 130 and thecenter plate 120 can have ridges or grooves that are configured toengage each other to prevent relative movement between them. The keyingstructures can be provided in suitable locations around a perimeter ofthe center plate 120. Expansion is typically less of an issue inrecessed cavity filter plates; however, keying or other interlockingstructures could be used in such filter plate assemblies, if desired.

As shown for example in FIGS. 12, 14, 15, and 17, in someconfigurations, each center plate or movable plate 120 is provided witha wash apparatus 300 or components of a wash apparatus 300. The washapparatus 300 is connected to a wash fluid source 400 which supplieswater or other wash fluid. The wash apparatus 300 comprises a firstsprayer assembly or spray nozzle 310, a second sprayer assembly or spraynozzle 320, a pair of fluid hoses 340 (shown in FIGS. 5 and 9), and aconnecting pipe 330 between each fluid hose 340 and each sprayerassembly or spray nozzle 310, 320. Alternatively, instead of providing aconnecting pipe 330, each fluid hose 340 can be directly connected tothe respective sprayer assembly 310, 320. Each sprayer assembly 310, 320resides exterior to each of the first filter plate 130, the secondfilter plate 130, and the center plate or movable plate 120. Aconnection is provided between the sprayer assemblies 310, 320 and thecenter plate or movable plate 120, to secure the sprayer assemblies 310,320 to the center plate or movable plate 120. Preferably, the firstsprayer assembly 310 is configured to wash or clean one side of thecenter plate or movable plate 120 and/or one of the first and secondfilter plates 130, and the second sprayer assembly 320 is configured towash or clean the other side of the center plate or movable plate 120and/or the other filter plate 130. As shown in FIGS. 16 and 17, thesprayer assemblies 310, 320 move downward with the center plate ormovable plate 120, such that the sprayer assemblies 310, 320 wash orclean the first and second filter plates 130 as the center plate ormovable plate 120 is moved downward (or upward) relative to the firstand second filter plates 130. However, in other embodiments, the sprayerassemblies 310, 320 can be configured to wash or clean the first andsecond filter plates 130 and the center plate or movable plate 120 froma stationary position relative to the first and second filter plates130. Carrying the spray nozzles and/or other portions of the washapparatus on a filter plate that defines a portion of a filter chamberallows for fully or partially automatic washing at a lower cost thanexisting systems because less additional structure is required. That is,existing systems provide spray nozzles on a support structure that isentirely separate from the filter plates, which results in a higheroverall cost than the illustrated arrangement. In other configurations,the filter press 10 may not include a wash apparatus and the filterplates can be manually cleaned or cleaned using a separate cleaningdevice (e.g., a spray pressure washer).

The sprayer assemblies 310, 320 can be configured to discharge washfluid at a high pressure (and low volume). Given that the filter plateassembly 100 can comprise a large number of center plates 120 and,therefore, a large number of sprayer assemblies 310, 320, configuringthe sprayer assemblies 310, 320 to discharge wash fluid at a highpressure typically requires a high-quality fluid pump capable ofmaintaining the high pressure throughout all of the sprayer assemblies310, 320, which are connected in parallel. Where use of such a pump iscost prohibitive or where use of such a pump is technically infeasibleor difficult, the sprayer assemblies 310, 320 can also be configured todischarge wash fluid at a relatively low pressure (and high volume), forexample approximately 100 psi (and approximately 500 GPM). The pumprequired for such an arrangement has a lower cost than a high pressurepump therefore allowing the overall assembly to have a lower cost. Itwas unexpectedly discovered by the Applicant that a high volume, lowpressure (HVLP) wash arrangement effectively cleans the filter plates.Other pressures and volumes are also possible. It is also possible toconfigure the sprayer assemblies 310, 320 such that the sprayerassemblies 310, 320 for only a subset of the center plates 120 (e.g.,roughly a third of the sprayer assemblies 310, 320) discharge wash fluidat any given time. By configuring the sprayer assemblies 310, 320 insuch way that only a subset of the sprayer assemblies 310, 320 dischargewash fluid at any given time, it is possible to maintain a high waterpressure with a lower quality (or lower pressure) fluid pump.

Although multiple force generators 510 are illustrated (one for eachcenter plate 120), in other arrangements a single force generator can beprovided that is coupled (or that can be coupled) to multiple centerplates 120, such as a sub-set or all of the center plates 120.Furthermore, although the center plates 120 are illustrated as moving ina vertical direction and below the first and second filter plates 130,other arrangements are also possible. For example, the center plates 120can be configured to move upward, to either lateral side, in obliquedirections relative to the first and second filter plates 130, in aswinging or rotational motion, or any other movement displaced from theoperational axis.

Another embodiment is shown in FIGS. 20-22. Components, features, andadvantages of other embodiments, that are not otherwise described orshown in FIGS. 20-22, can be included in this embodiment. Additionally,components, features, and advantages of this embodiment can be includedin other embodiments.

In the embodiment of FIGS. 20-22, a filter plate assembly 100 for filterpress 10 comprises a first filter plate or movable plate 140 having arecessed cavity 144 and a corresponding filter plate or second filterplate 150. The surface of the filter plate 150 facing the movable plate140 cooperates with the movable plate 140 to form a filter chambercomprising the recessed cavity 144. In some embodiments, the surfaces ofthe filter plate 150 facing the filter chamber and bounding the filterchamber opening in the closed position are planar or generally planarsuch that the entire thickness of the filter chamber is defined by therecessed cavity 144 of the movable plate 140. For example, the thicknessof the filter chamber can be defined by the depth of the recessed cavity144. In other embodiments, the surface of the filter plate 150 facingthe movable plate 140 can include a recessed cavity 154 (not shown) thatcooperates with the recessed cavity 144 of the movable plate 140 to forma filter chamber. In such an embodiment, the thickness of the filterchamber is defined (at least in part) by the recessed cavities 144, 154.For example, the thickness of the filter chamber can be defined by thecombined depth of recessed cavities 144, 154.

The movable plate 140 and the filter plate 150 can be keyed together.For example, the side of movable plate 140 facing the filter plate 150can have key recesses 142 (shown in FIGS. 20 and 22) that are adapted tomate with corresponding keys of the filter plate 150. The key recess 142can be a hole or other structure that is configured to receive astructure on the filter plate 150. Alternatively, the movable plate 140can have keys or protrusions that are configured to be received withinkey recesses of the filter plate 150. In other embodiments, the filterplate 150 and the movable plate 140 can have ridges or grooves that areconfigured to engage each other to prevent relative movement betweenthem. The keying structures can be provided in suitable locations arounda perimeter of the movable plate 140.

As shown in FIGS. 21 and 22, the movable plate 140 preferably rides orslides within a pair of vertical rails 18. The vertical rails 18 allowthe movable plate 140 to move between an aligned position (shown in FIG.21) and a separated position (shown in FIG. 22) relative to the filterplate 150. The filter plate assembly 100 can include any number ofmovable plates 140 and corresponding or second filter plates 150 for usewith a filter press 10. In some configurations, as shown in FIG. 21,each movable plate 140 is provided with a wash apparatus 300 orcomponents of a wash apparatus 300. The wash apparatus 300 can have thesame components and features as that described above in connection withthe embodiments of FIGS. 1-19 and shown for example in FIGS. 12, 14, 15,and 17.

FIGS. 23-25 show a filter press 10 incorporating a plurality of filterplate assemblies 100, which omits the force generator 510 for each ofthe movable filter plates 120. In some configurations, the number offorce generators 510 is less than the number of movable filter plates120. In some configurations, a force generator 510 can be provided ateach end of the stack of filter plate assemblies 100.

The force generator 510 or force generators 510 can act on the movablefilter plates 120 through a force transfer element or mechanism, such asa beam (e.g., an I-beam 600). In some configurations, the force transferelement may be a linking element or linking mechanism, which links twoor more of the movable filter plates 120. The term “link” as used hereinmeans that the linking element acts upon two or more movable filterplates 120, which can include simply contacting the movable filterplates 120 or the linking element can be connected to two or more of themovable filter plates 120. The linking element 600 can engage more thanone of the movable filter plates 120 to selectively move the movablefilter plates 120. One or more force generators 510 can be configured tomove the linking element.

The movable filter plates 120 can be supported by rails 18 in a mannersimilar to the embodiments described above. However, in otherconfigurations, the movable filter plates 120 can be otherwisesupported. For example, the movable filter plates 120 can be restrainedin whole or in part by the side rails 12 of the filter press 10.

In some configurations, a portion or an entirety of the filter press 10may be located on a scale or load cell arrangement such that the weightof the filter plate assembly (alone or in combination with othercomponents of the filter press) can be determined. Such an arrangementcan allow for a tare weight to be established, which can then allow forcomparisons to weights at different points in the filtering process,including discharging and cleaning steps. Such an arrangement can allowfor or facilitate a fully autonomous filter press by allowing the systemto monitor the filling of the filter chambers with filter cake andconfirm complete discharge of the filter cake and/or determine ifadditional cleaning is required. For example, one impediment toautonomous filter presses is a concern over incomplete removal of filtercake between filtering cycles. Cake residue at the beginning of a filtercycle can result in pressure differential between the portion of thefilter chamber having the cake residue and adjacent portions of thefilter chamber. This differential can result in undesirable stress onthe filter plates, which over a period of time can weaken and possiblyresult in failure of the filter plate. As a result, many users opt formanual cleaning or at least manual inspection of the filter platesbetween cycles so that cake residue can be avoided. However, suchcleaning or manual inspection is time-consuming (and, thus, expensive)and difficult.

Although the present invention has been described in terms of certainembodiments, other embodiments apparent to those of ordinary skill inthe art also are within the scope of this invention. Thus, variouschanges and modifications may be made without departing from the spiritand scope of the invention. For instance, various components may berepositioned as desired. Moreover, not all of the features, aspects andadvantages are necessarily required to practice the present invention.Accordingly, the scope of the present invention is intended to bedefined only by the claims that follow.

What is claimed is:
 1. A filter plate assembly, comprising: a firstfilter plate having a first face and a first edge surface coincidingwith a first edge of the first filter plate; and a second filter platehaving a second face and a second edge surface coinciding with a secondedge of the second filter plate, the second edge of the second filterplate facing in a same direction away from an operational axis as thefirst edge of the first filter plate; wherein the first filter plate andthe second filter plate have a filtering position in which the platesare aligned with one another along the operational axis and the firstface and the second face cooperate to define opposing ends of a filterchamber, wherein the first face is configured to support a first filtermedia and the second face is configured to support a second filtermedia, wherein a particulate cake formed within the filter chamber has amaximum width equal to a distance between the first face and the secondface in a direction along the operational axis; wherein the first filterplate is movable out of alignment with the second filter plate in adirection perpendicular to and away from the operational axis to adischarge position in which the particulate cake can be discharged froma portion of the filter chamber defined by the at least one of the firstfilter plate and the second filter plate, wherein, in the dischargeposition, the first edge surface is located in a position past thesecond edge surface.
 2. A filter plate assembly, comprising: a firstfilter plate having a first side surface and a first edge surface, thefirst side surface comprising a first cavity and the first edge surfacecoinciding with a first edge of the first filter plate; and a secondfilter plate having a second side surface and a second edge surface, thesecond side surface comprising a second cavity and the second edgesurface coinciding with a second edge of the second filter plate, thesecond edge of the second filter plate facing in a same direction awayfrom an operational axis as the first edge of the first filter plate;wherein the first filter plate and the second filter plate have afiltering position in which the plates are aligned with one anotheralong the operational axis and the first cavity and the second cavitycooperate to define a filter chamber with the first side surface and thesecond side surface define opposing ends of the filter chamber, whereinthe first side surface is configured to support a first filter media andthe second side surface is configured to support a second filter media,wherein a particulate cake formed within the filter chamber has amaximum width equal to a combined depth of the first cavity and thesecond cavity in a direction along the operational axis; wherein atleast one of the first filter plate and the second filter plate is amovable plate that is movable in a direction perpendicular to and awayfrom the operational axis and out of the filtering position to adischarge position in which the particulate cake within the respectiveone of the first cavity and the second cavity can be discharged,wherein, in the discharge position, the first edge surface is located ina position past the second edge surface.
 3. The filter plate assembly ofclaim 2, further comprising a force generator configured to exert aforce to hold the movable plate in the filtering position or return themovable plate to the filtering position.
 4. The filter plate assembly ofclaim 3, wherein the force generator is a pneumatic cylinder whichutilizes a compressed gas as its operating fluid, a hydraulic cylinderthat utilizes an incompressible fluid, an electric cylinder, or a screwjack.
 5. The filter plate assembly of claim 2, wherein, in the dischargeposition, a portion or all of the movable plate is located outside of aspace bounded by side edges of the other of the first filter plate andthe second filter plate.
 6. The filter plate assembly of claim 2,further comprising a first sprayer assembly attached to the movableplate at a location outside of the cavity, the first sprayer assemblyconnected to a wash fluid source.
 7. The filter plate assembly of claim6, wherein the first sprayer assembly is configured to direct a spray ofwash fluid toward at least one of the other of the first and secondfilter plates and a third filter plate adjacent an opposite side of themovable plate from the other of the first and second filter plates. 8.The filter plate assembly of claim 6, further comprising a secondsprayer assembly attached to the movable plate, the second sprayerassembly connected to the wash fluid source.
 9. The filter plateassembly of claim 8, wherein the second sprayer assembly is configuredto direct a spray of wash fluid in a direction opposite the firstsprayer assembly.
 10. The filter plate assembly of claim 2, furthercomprising at least one support structure that movably supports themovable plate.
 11. The filter plate assembly of claim 10, wherein the atleast one support structure comprises a first side track and a secondside track located on opposite sides of the movable plate.
 12. A filterplate assembly, comprising: a first filter plate having a first sidesurface; a second filter plate having a second side surface; a centerplate having an outer surface and an interior region, said center plateconfigured to be movable between an aligned position and a separatedposition relative to the first filter plate and the second filter plate,wherein the first side surface is configured to support a first filtermedia and the second side surface is configured to support a secondfilter media, wherein a particulate cake formed within the filterchamber has a maximum width equal to a depth of the center plate in adirection along the operational axis, wherein in said aligned positionthe center plate is held in place between the first side surface and thesecond side surface and a perimeter seal is created around the interiorregion between the center plate and the first side surface of the firstfilter plate and between the center plate and the second side surface ofthe second filter plate, and wherein in said separated position thefirst filter plate and the second filter plate separate from the centerplate a distance, said distance permitting the center plate to drop ormove toward or to the separated position, whereupon the particulate cakeis discharged can be discharged from the interior region of the centerplate.
 13. The filter plate assembly of claim 12, further comprising aforce generator configured to exert a force to hold the center plate inplace between the first side surface and the second side surface in saidaligned position or return the center plate to the aligned position. 14.The filter plate assembly of claim 13, wherein the force generator is apneumatic cylinder which utilizes a compressed gas as its operatingfluid, a hydraulic cylinder that utilizes an incompressible fluid, anelectric cylinder, or a screw jack.
 15. The filter plate assembly ofclaim 14, wherein said separated position is attained when thecompressed gas is released from the pneumatic cylinder.
 16. The filterplate assembly of claim 12, wherein, in the separated position, aportion or all of the center plate is located below a first bottomsurface of the first filter plate and a second bottom surface of thesecond filter plate.
 17. The filter plate assembly of claim 12, furthercomprising a first sprayer assembly attached to the outer surface of thecenter plate, said first sprayer assembly connected to a wash fluidsource.
 18. The filter plate assembly of claim 17, wherein the firstsprayer assembly is configured to direct a spray of wash fluid toward atleast one of said first side surface and said second side surface. 19.The filter plate assembly of claim 17, further comprising a secondsprayer assembly attached to the outer surface of the center plate, saidsecond sprayer assembly connected to the wash fluid source.
 20. Thefilter plate assembly of claim 19, wherein the second sprayer assemblyis configured to direct a spray of wash fluid toward at least one ofsaid first side surface and said second side surface.
 21. The filterplate assembly of claim 12, further comprising at least one supportstructure that movably supports the center plate.
 22. The filter plateassembly of claim 21, wherein the at least one support structurecomprises a first side track and a second side track located on oppositesides of the center plate.
 23. The filter plate assembly of claim 2,wherein the movable plate is movable in a vertical direction from thefiltering position to the discharge position.